Machine for conditioning leather surfaces



June 30, 1942. J. H. KELLY 2,287,999

MACHINE FOR CONDITIONING LEATHER SURFACES Filed May 7, 1940 t 2 Sheets-Sheet, l

OR H 6 A ATTORNEY June 30, 1942. J. H. KELLY MACHINE FOR CONDITIONING LEATHER SURFACES Filed May 7, 1940 2 Sheets-Sheet 2 W WM" Z 2 l wag-r0? W ATTORNEY I Patented June 30, 1942 MACHINE FOR CONDITIONING LEATHER SURFACES John H. Kelly, Pittsburgh, Pa.

Application May 7, 1940, Serial No. 333,783

12 Claims.

This invention relates generally to the conditioning of leather surfaces preparatory to alfixing them to other pieces of leather or other material with a cementitious substance and more particularly to the character of the conditioned surface together with the machine and the method by which it is produced.

This is a continuation in part of my patent application Serial No. 257,629, filed February 21, 1939.

This invention may be advantageously employed as a step in the process of joining pieces of leather to one another, such as splicing belts, and other leather articles, but is particularly adapted for conditioning soles, employed in the process of making or repairing boots, shoes and the like. I

In conditioning a leather surface preparatory to attaching it to another object by the application of a cement, the surface should be clean or free from loose flesh fibers because they readily pull away from the leather and thus produce a weak bond. To increase the strength of the bond a ribbed surface is formed in the close fibers of the leather. This increases the effective area on which the cement is applied and also increases the permeability of the close fibers by the cementiticus substance.

The practice of producing a ribbed surface in soles for repairing shoes has been carried out to some extent by the use of hand tools and roughing cutters. The hand tools scratch up the fibers, producing a rough stringy surface which is undesirable. When a leather sole is placed on a board and held hard against a cutter by hand, the cutter removes a portion of the loose flesh fibers but presses the remaining loose flesh fibers into the surface of the leather. These fibers afterwards rise from the surface and weaken the cement bond, causing the joint to fail.

The principal object of this invention is the provision of an improved process for forming a series of parallel ridges with alternate grooves to produce a marginal band around the perimeter of shoe soles which conditioned surface is clean and uniform.

Another object is the provision of a machine for carrying out this process.

Another object is the provision of an improved means for feeding the leather as it passes over the cutter.

Another object is the provision of an improved pressure roll for controlling the movement of the leather as it passes through the machine to produce a conditioned marginal band in the surface thereof.

Other objects and advantages appear hereinafter in the following description and claims.

In the accompanying drawings a practical embodiment illustrating the principles of this invention is shown wherein:

Fig. 1 is a front elevation of the machine comprising this invention.

Fig. 2 is a side elevation of the machine showing the relative position of the feed roll and the cutter.

Fig. 3 is a top plan view of the machine shown in Figs. 1 and 2.

Fig. 4 is an enlarged detail view showing the table, the cutter and the feed roll in side elevation with the cover plate enclosing the cutter removed.

Fig. 5 is a plan view of the table and the cutter taken on the line 55 of Fig. 4.

Referring to Figs. 1, 2 and 3 of the drawings, 10 is the base casting of a leather conditioning machine having the aligned bearings H and [2 formed integral therewith and arranged to rotatably support the horizontal shaft l3. A pulley I4 is secured to the end of the shaft l3 adjacent the bearing l2 and arranged to receive power through a belt drive preferably connected directly to a motor as shown. A cutter I5 is secured to the other end of the shaft l3 adjacent the bearing l l.

The cutting faces of the teeth which are to be used face the front of the machine and the shaft I3 is rotated in a clockwise direction in Fig. 2. The cutter employed is provided with dual cutting faces and it may be turned around on the shaft or the direction of rotation of the shaft may be reversed. However it is preferable to feed the leather toward the front of the machine and in the direction of the rotation of the cutter.

The table l6 encloses the cutter l5 and is fastened to the side of the casting I 0. This table is provided with the horizontally disposed surface I! which is polished and has an opening l8 intermediate of its ends to permit the teeth of the cutter IE to extend thereabove any suitable height such as approximately one thirty-second of an inch. A removable plate 19 covers the side of the table l6 completely enclosing the cutter and is provided with a polished top surface forming a part of the table surface I! and which bounds one side of the opening IS.

The extent of the opening I 8 is preferably just enough to permit the top row of teeth of the cutter I5 to extend slightly above the table surface I'I. However the edge 20 of the opening I8, which is adjacent the front of the machine, is spaced a little further from the cutter than the opposite edge, to allow for the passage of cuttings down through the opening.

These cuttings pass down through the table l6 and are deposited in the drawer 2| which is slidably supported on the bed plate that carries the casting ID. The upper portions of the sides of the drawer 2| are arranged to engage the outer faces of depending flanges on the lower edge of the plate l9 and the inner side of the table IE to guide the movement of the drawer. The front and rear walls of the drawer engage the front and rear walls respectively of the table as shown in Fig. 4, thereby limiting the inward movement of the drawer. The cuttings may be readily removed by sliding the drawer out of the machine.

The flesh side of a leather shoe sole is placed on the polished table surface l1 and moved into engagement with the cutter. The ridges and grooves are accurately and uniformly formed in the flesh side, leaving a clean surface because of the character of the cutter and the pressure roll 22. In this machine the leather is preferably moved in the same direction that the cutter rotates but at a much slower speed. In other leather roughing machines the cutter, spiked wheel, brush or sander is rotated in the direction opposite to the movement of the leather and it is ordinarily necessary to provide feeding and withdrawing rolls on opposite sides of the cutter to force the work against the movement cutter.

In the present machine the movement of the leather therethrough is controlled by means of the single feed and pressure roll 22, the cylindrical perimetral surface of which is made of resilient material such as soft rubber, vulcanized on the metal core 23. This pressure roll is approximately one inch wide and is mounted on the shaft 24 carried in the aligned spaced bearings 25 and 26 formed integral with the hinged frame 21.

The frame 21 extends rearwardly from each of the bearings 25 and 26 and is pivotally supported on the fulcrum pin 28 which in turn is carried in aligned holes in the upwardly projecting arms 29 formed integral with the casting and is locked by the set screw 30.

The frame 21 is thus hingedly supported to the base casting and moves about the axis of the pin 28. An adjustable stop or abutment bolt 3| is arranged to screw into a tapped hole in the top of the bearing l2. The underside of the frame 21 is arranged to engage the head of the abutment bolt 3| to provide an opening or throat between the rubber roll 22 and the cutter I and to prevent the rubber roll from engaging the cutter. This abutment bolt may be locked in the adjusted position by the jam nut 32 as shown in Fig. 1. A coil spring 33 is attached at its upper end to the hinged frame 21 and at its lower end to the base casting ID to hold the frame 21 against the stop or abutment bolt 3|. When a piece of leather is fed into and through the throat between the pressure roll and the cutter the thickness of the leather lifts the pressure roll and increases the tension on the spring 33. The tension of the spring together with the lever arm of the frame 21 determines the ultimate'pressure exerted on the leather passing under the rubber roll. The resiliency of the rubber roll causes it to flatten against the top surface of the leather.

The pressure is thus transmitted through a relatively broad area rather than a line contact to the leather surface.

The pressure exerted by the rubber roll on the leather may be adjusted to compensate for different shoe sole thicknesses by varying the initial tension of the spring 33. This is accomplished by changing the relative position of the nut 34 on the threaded rod 35, the lower end of which is provided with a hole to receive the hook formed on the upper end of the spring. The actual pressure on the leather sole should be sufficient to produce a clean conditioned surface free from loose and stringy fibers.

A crank handle 36 is secured to the end of the shaft 24 for manually turning the rubber roll 22. This handle may be turned in either direction and thus the leather sole may be fed against or with the direction of rotation of the cutter. It is preferable to feed the sole in the same direction that the cutter revolves. To do this, the handle is rotated in a counterclockwise direction in Fig. 2 which is a natural motion for the operator who is facing the machine and the leather sole is started into the throat from the rear of the machine and passed to the front.

The cutter I5 is preferably formed from a cylindrical blank approximately one and ninesixteenths of an inch in diameter having a perimetral face one inch in width. A series of twenty annular parallel grooves 31 are cut in the face of the blank forming the ridges or crests 38 of the teeth. The grooves 31 are preferably cut to a depth of twenty-two thousandths of an inch. However they may be cut to a greater depth but no material advantage is gained thereby, since a deeper tooth would remove more of the leather than is ordinarily necessary.

Uniformly spaced transverse flutes 39 are then cut through the full width of the blank to produce a series of transverse land sections 40. Each land section is thus provided with a series of twenty teeth in the surface thereof. In a blank of one and nine-sixteenths of an inch in diameter, it is preferable to cut twenty of the flutes 39, each of which is three thirty-seconds of aninch wide, thereby providing twenty land sections five thirty-seconds of an inch wide. The ridges 38 of the teeth in each land section extend in the same cylindrical plane and should not be backed off.

The transverse flutes 39 are preferably cut to the depth of one-quarter of an inch to provide suificient space to receive the leather cuttings, otherwise it would not be necessary to cut them any deeper than the depth of the grooves 31.

The side walls of the flutes 39, to the depth of annular grooves 31, form the dual cutting profile of the teeth on the land sections. The planes of both wall surfaces of each flute are disposed tangential to the opposite sides of an imaginary cylinder of one fourth of an inch in diameter and coaxial of the cutter. Thus each land section provides two cutting profiles, one on either side of the land and, because of the construction explained above, a cutting profile lags one eighth inch when rotated in a cutting direction. Thus the flutes may be formed by first drilling transverse holes 4| through the blank and then cutting away the perimetral surface of the blank by a V-shaped milling cutter, the faces of which are disposed at an angle of approximately 25 to each other to produce the proper lagging of the cutting faces of the teeth. The drilled holes 4| thus provide adequate space for receiving the leather cuttings and also for the purpose of providing clearance for a V-shaped grinding wheel having the same angularly disposed cutting faces which are used in resharpening the cutting profiles of the teeth.

By making the cutter 15 in this manner the teeth on each land section 46 have two cutting profiles, depending upon the direction of rotation of the cutter. Thus the cutter may be positioned on the machine, disregarding the direction of rotation. When one cutting profile has become dull the cutter may be reversed on the machine and the second cutting profile may be used until it becomes dull, at which time both cutting profiles may be resharpened with a V- shaped grinding wheel in one operation. The grinding surface of the resharpening wheel must provide the same degree of lag in the cutting faces, regardless of the width of the flutes 39.

When the width of the flutes 39 of a cutter one and nine sixteenths of an inch in diameter become wider than three sixteenths of an inch due to resharpening the cutter, it will be found that the teeth snag into the leather and eject it forcefully from the machine. This is true reardless of the number of rows of teeth or remaining width of the land sections. When the teeth of the cutter have been sharpened a sufficient number of times to produce a slot of this width the cutter will have served its useful purpose. This limitation in the flute width is directly proportional to the diameter of the cutter and not to the number of land sections or to the width of the land sections.

The cutter I is provided with the bore 42 for receiving the end of the shaft 13. A shoulder is provided on the shaft l3 to limit the insertion of the cutter thereon.

The end of the shaft I3 is provided with a tapped hole for receiving the cutter retaining screw 43. A retaining washer M is placed under the head of the screw 43 and is arranged to engage the end of the cutter and clamp it against the shoulder on the shaft l3. It is preferable to employ a screw thread which will tighten the screw and clamp the cutter when the latter is being rotated by the machine.

When the cutter I5 is provided with teeth approximately .022 of an inch deep it is preferable to have the full height of the teeth extend above the polished table surface 11. The table I6 merely protects the operator from being harmed by the rotary cutter and provides means for catching and directing the cuttings into the drawer 2|.

The leather upon passing through the throat between the rubber roll 22 and the cutter I5 is wholly supported by these two members and the table surface 11 takes no part in the function of forming a ribbed conditioned surface in the leather. This further explains the reason for a limited width of the flutes 39 of the cutter IS.

The pressure exerted on the leather in the throat of the machine must be suflicient to remove the flesh fibers and produce a cleaned conditioned surface free of loose and stringy fibers. If the pressure exerted through the rubber roll 22 is too light the teeth of the cutter will not penetrate to their full depth and there will be a tendency for the teeth to kick the leather out of the machine because of the small frictional engagement between the rubber roll and the leather which is substantially linear. As the pressure is increased to force the leather against the teeth of the cutter and cause them to cut to their full depth, the soft rubber roll flattens and produces a greater frictional engagement on the leather, thereby providing full control of the movement of the leather in the machine. In fact the movement of the leather may be stopped by holding the crank 36 from turning while the cutter continues to rotate. Under this condition the teeth will cut to their full depth and thereafter burnish the cut surface without harm thereto.

During the operation of the machine the continued engagement of the cutting profiles of the teeth on the consecutive land sections produces a vibration in the leather which is resisted and absorbed to a considerable extent, by the soft rubber roll.

This cutting action of the teeth also has the tendency to feed the leather through the machine. If the crank handle 36 was not held the work would be thrown out of the machine. Thus when the leather is fed through the machin in the same direction as the rotation of the cutter the movement of the crank handle 36 is retarded by the operator. The cutting action of the teeth actually feeds the work through the machine and the controlled movement of the crank by the operator acts through the frictional engagement by the rubber roll to determine movement of the leather. Thus the operator controls the cutting operation by holding back the movement of the leather.

On the other hand if the Work is passed through the machine in a direction opposite to the rotation of the cutter the operator must exert sufiicient energy to the crank to overcome the cutting resistance of the teeth and drive the work through the machine. In this instance the operator controls the cutting operation by positively forcing the leather through the machine.

It is preferable to operate the machine so that the cutting action of the teeth becomes the propelling force on the leather and the rubber roll merely arrests the movement of the leather and becomes a controlling pressure roll rather than a feeding roll.

The soft rubber roll 22 has many important advantages contributing to the novelty of this invention. It provides proper frictional engagement for controlling the movement of the leather through the machine without harming the grain or finished surface of the sole. In conditioning the flesh surface of a full sole the operator inserts one side of the shank portion of the sole in the throat of the machine and manually directs it under the pressure of the rubber roll, around the full sole, using the perimeter as a guide, thereby producing a marginal band of ridges and grooves parallel to each other and to the perimeter of the sole. The resiliency of the rubber pressure roll 22 permits the leather to be turned thereunder for following the sharp curvatures of the perimeter of the sole while maintaining the grooves in their parallel relation. In the case of a half sole the grooves may be cut at right angles to the edge of the shank waist.

Since the grooves of the conditioned surface are parallel with the perimeter of the sole for the full extent thereof, the cementitious substance flows around the grooves rather than being extruded out the sides when the shoe and its new sole are subjected to pressure in the cement press.

The resilient pressure roll 22 may be mechanically driven, as by the motor which drives the cutter l5 through a series of gears. The speed of this roll must naturally be slower than that of the cutter. This speed reduction may be obtained through this train of gears. As described above the direction of rotation of the rubber roll is optional but it is preferable that the work travels in the direction of the rotation of the cutter.

If a larger diameter cutter I5 is employed a greater number of land sections may be formed in the perimetral surface thereof. The grooves defining these land sections must necessarily be wider than three thirty seconds of an inch when the cutter is new to provide the same bite for the cutting profile of the teeth as that described above because of the greater radius of curvature. In a larger diameter cutter it is preferable to form the land sections five thirty seconds of an inch, which is the same width as that described above. However it will be found that the plane which is common to the cutting profile of the teeth should not lag as much as one eighth of an inch. The plane of the cutting profile of the teeth of the one and nine sixteenths inch cutter described above, may have a zero lag or be truly radial when the cutter is new, but the degree of lag should be increased as the grooves of the cutter are widened by repeated sharpening. The limit of the degree lag of the cutting profile plane is one eighth of an inch from the axial center of the cutter. The limit of the degree of lag for a larger diameter cutter will be correspondingly less or in proportion to the radius of the curvature.

For commercial practice it is preferable to furnish these cutters with the cutting profile plane disposed at the limiting degree of lag. The operator may then be provided with standard resharpening equipment which maintains this lag of the cutting profile during the useful life of the cutter which simplifies the resharpening operation and avoids the use of an intricate and costly machine which would automatically increase the lag of the cutting profile from zero to the limit of lag as the cutter is being worn away by resharpening.

I claim:

1. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, consisting of a rotary driven cutter having teeth on its perimetral surface for producing the conditioned surface, a pressure roll having a resilient perimetral portion and rotatably supported to cooperate with the cutter in forming a throat through which the leather passes, and means to rotate the pressure roll for controlling the movement of the leather passing through the throat.

2. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, consisting of a rotary driven cutter having teeth on its perimetral surface for producing the conditioned surface, a pressure roll having a resilient perimetral portion and rotatably supported to cooperate with the cutter in forming a throat through which the leather passes, and means for rotating the pressure roll in either direction independently of said cutter.

3. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, consisting of a rotary driven cutter having teeth on its perimetral surface for producing the conditioned surface, a pressure roll having a resilient perimetral portion and rotatably supported to cooperate with the cutter in forming a throat through which the leather passes in the direction of the movement of the rotary cutter, and means to rotate the pressure roll, the speed of movement of the leather passing through the throat being regulated by the speed of rotation of the pressure roll,

4. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, consisting of a rotary driven cutter having teeth on its perimetral surface for producing the conditioned surface, a frame capable of movement toward and away from the plane of the axis of said cutter, a rotatable pressure roll having a resilient perimetral surface carried by said frame and arranged to cooperate with the cutter in forming a throat through which the leather passes, stop means engaging said frame to limitthe gap between the perimetral surfaces of the cutter and the roll, means for resiliently urging the frame against said stop, and means to rotate the pressure roll for controlling the movement of the leather passing through the throat.

5. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, consisting of a rotary driven cutter having teeth on its perimetral surface for producing the conditioned surface, a pressure roll having a resilient perimetral portion and rotatably supported to cooperate with the cutter in forming a throat through which the leather passes, means to rotate the pressure roll for controlling the movement of the leather passing through the throat, and means enclosing the cutter for collecting the cuttings removed from the surface of the leather.

6. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, which consists of a support, a pair of parallel shafts journaled in said support with their ends extending beyond one side thereof, means secured to the end of the first shaft for producing the conditioned surface, a roll having a resilient perimetral portion secured to the end of the second shaft and arranged to cooperate with said first mentioned means in forming an open throat through which the leather passes, means for driving the first shaft, and means to rotate the second shaft and the roll independently of the rotation of the first shaft to control the passage of the work through the throat.

7. A machine for conditioning the surface of leather preparatory to' receiving a cementitious substance, which consists of a support, a pair of parallel shafts journaled in said support with their ends extending beyond one side thereof, means secured to the end of the first shaft for producing the conditioned surface, a roll having a resilient perimetral portion secured to the end of the second shaft and arranged to cooperate with said first mentioned means in forming an open throat through which the leather passes, means for driving the first shaft, and means for manually rotating the second shaft and the roll independently of the rotation of the first shaft to control the passage of the work through the throat.

8. In a machine for conditioning the surface of leather preparatory to receiving a cementitious substance, the combination of a support, means carried by said support to produce the conditioned surface, driving means for rotating the first mentioned means, a pressure roll having a resilient perimetral portion rotatably carried by said support to cooperate with the first mentioned means in forming a throat through which the leather passes, and means to rotate the pressure roll in either direction for controlling the movement of the leather through the throat.

9. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, which consists of a support, a shaft journaled in said support, means mounted on said shaft for producing the conditioned surface, means for rotating said shaft, a frame having one end hinged to the upper portion of the support, spring tension means connecting the other end of the frame to the support, a shaft parallel to the first mentioned shaft and journaled in said support intermediate of its hinge and the tension means, a resilient roller fixed on the second shaft and arranged to cooperate with the first mentioned means to form a throat through which the leather passes, and means for rotating the second shaft.

10. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, which consists of a support, a shaft journaled in said support, means mounted on said shaft for producing the conditioned surface, means for rotating said shaft, a frame having one end hinged to the upper portion of the support, adjustable spring tension means connecting the other end of the frame to the support, a shaft parallel to the first mentioned shaft and journaled in said support intermediate of its hinge and the tension means, a resilient roller fixed on the second shaft and arranged to cooperate with the first mentioned means to form a throat through which the leather passes, and means for rotating the second shaft.

11. A machine for conditioning the surface of leather preparatory to receiving a cementitious substance, which consists of a support, a shaft journaled in said support, means mounted on said shaft for producing the conditioned surface, means for rotating said shaft, a frame having one end hinged to the upper portion of the support, spring tension means connecting the other end of the frame to the support, a shaft parallel to the first mentioned shaft and journaled in said support intermediate of its hinge and the tension means, a resilient roller fixed on the second shaft and arranged to cooperate with the first mentioned means to form a throat through which the leather passes, means for rotating the second shaft, and means for limitingthe approach of the roller toward the first mentioned means.

12. A machine for forming a marginal band of ridges and intervening grooves around the perimetral portion of a shoe sole, which consist of a support, a pair of parallel shafts journaled in said support and protruding therefrom, continuously driven means for rotating one of the shafts, means secured on the protruding end of one of said shafts to produce the ridges and grooves, a roll having a resilient perimetral surface secured on the protruding end of the second shaft, means to manually drive said second shaft, said first mentioned means and said roll cooperating to form an open sided throat for the passage of the sole whereby the sole during its passage may be turned in a horizontal plane to properly locate the band relative to the perimetral edge of the sole.

JOHN H. KELLY. 

